One vertex per element, one color per generator, with an edge from x to x·s.
(9,10)(11,14)(12,19)(13,15)(16,20)(17,23)(18,21)(22,24)(25,26,31,33)(27,34,37,30)(28,32,38,29)(35,36,40,39)(1,2,5,4)(3,7,8,6)(9,11,13,18)(10,14,15,21)(12,17,20,24)(16,22,19,23)(25,27)(26,30)(28,35)(29,36)(31,37)(32,39)(33,34)(38,40)(1,3,5,8)(2,6,4,7)(10,15)(14,21)(16,19)(22,23)(25,28,31,38)(26,32,33,29)(27,35,37,40)(30,39,34,36)(1,3,5,8)(2,7,4,6)(9,10)(11,14)(12,16)(13,15)(17,22)(18,21)(19,20)(23,24)(25,26)(27,30)(28,32)(29,38)(31,33)(34,37)(35,39)(36,40)(1,3)(2,7)(4,6)(5,8)(9,11)(10,14)(12,17)(13,18)(15,21)(16,22)(19,23)(20,24)(25,29,31,32)(26,28,33,38)(27,36,37,39)(30,35,34,40)(1,4,5,2)(3,6,8,7)(9,12,13,20)(10,16,15,19)(11,17,18,24)(14,22,21,23)(25,30)(26,27)(28,36)(29,35)(31,34)(32,40)(33,37)(38,39)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.